FR2802154A1 - PRIMARY GEARBOX DRIVE SYSTEM FOR A HYBRID-DRIVEN VEHICLE - Google Patents

Abstract

In this system, which is intended for a vehicle whose propulsion can be achieved from a heat engine (1) and / or an electric motor (2), the primary shaft (3) is integral with the rotor (20) of the electric motor (2); the system is remarkable in that the primary shaft (3) is mounted coaxially at one end of the crankshaft (10) of the heat engine (1), and that a clutch system (5, 6, 7) allows, selectively, either to join in rotation the crankshaft (10) with the primary shaft (3), or, on the contrary, to separate it. Driving a motor vehicle with hybrid propulsion.

Description

The present invention relates to a shaft drive system

  primary of the gearbox of a hybrid propulsion vehicle.

  By the expression "hybrid propulsion" is meant in the present

  description, and in the claims which follow, a propulsion which is carried out at

  from a heat engine and / or an electric motor, the vehicle being equipped

of these two types of engine.

  The advantage of such an arrangement is that it is possible, under certain conditions, to ensure the propulsion of the vehicle either only by means of the electric motor, or only by means of the heat engine, or both

  using the two motors, the torques of which add up.

  So it can be interesting for low speed traffic,

  for example on an urban trip, to use only the electric motor.

  On the contrary, for journeys outside built-up areas, use can be made

  either from the engine alone or from both engines at the same time.

  It is also interesting to be able to use the electric motor to start the internal combustion engine, the latter then ensuring the function

  traditionally assigned to the starter.

  More specifically, the present invention is intended for a drive system in which the primary shaft is integral with the rotor of the electric motor, its stator being fixed, for example integral with the casing of the gearbox. The objective of the invention is to propose a system of the kind mentioned above, which is of a simple design, of a reduced bulk, of a relatively low cost price, and capable of being implemented. by

  actuation means also simple and safe.

  This objective is achieved, in accordance with the invention, thanks to the fact that the primary shaft is mounted coaxially at one end of the crankshaft of the heat engine, and that a clutch system is provided which allows, selectively, either to fasten the crankshaft in rotation with the shaft

  primary, or, on the contrary, to dissociate it.

  Furthermore, according to a certain number of additional, non-limiting characteristics of the invention: - the dog clutch system is hydraulically operated; - The control means of the dog clutch system comprise an annular hydraulic piston, which coaxially surrounds the primary shaft and is mounted fixed in rotation and movable in axial translation; - This piston acts via a rotary link on a clutch sleeve integral in rotation with the primary shaft, but movable in axial translation thereon; - This piston is slidably mounted in a sleeve integral with the stator of said electric motor; - This piston is permanently biased by an elastic means such as a spring, which naturally tends to ensure the interconnection of the system in the absence of hydraulic pressure; - The shaft end of the crankshaft carries a flywheel, to which the dog clutch system is connected by means of a damping means working in torsion; the end portion of the primary shaft is centered and guided in rotation, by means of a rolling bearing, in a bore formed at

  the end of the crankshaft.

  Other characteristics and advantages of the invention will emerge from

  the description which follows, with reference to the accompanying drawings which represent a

  possible embodiment of the object of this invention.

  In the drawings, Figure 1 (single figure) is a general view, very

  schematic, of a drive system according to the invention.

  In this figure, the common axis XX has been designated by the reference XX 'to the crankshaft of the heat engine, referenced 10, and to the primary shaft of the

  gearbox, referenced 3, these two shafts being mounted end-to-end.

  Traditionally, the shaft 10 is driven by a motor

  thermal 1 of known type, gasoline or Diesel.

  The shaft 3 is the input shaft of a gearbox, also of

  known type, not shown, which is located on the left of the drawing.

  It can either be a manual transmission or

  an automatic gearbox.

  On the end 11 of the shaft 10 is fixed, in the usual manner, a

flywheel 4.

  The shaft 3 is guided in rotation, on the one hand, in a fixed bearing 301 * 35 (integral with the gearbox casing), on the other hand, by its free end portion 30 in a bore provided for the end of the shaft 10, this via

  a bearing 300, for example a needle bearing.

  Thus, the two shafts 10 and 3 are perfectly aligned along XX ', and are capable of rotating independently of one another around their common axis. The electric motor, referenced 2, comprises an annular stator 21, of axis XX ', which is carried by a fixed part 210, which is integral with the frame 211,

  for example the gearbox housing.

  The rotor 20, also annular, coaxially surrounds the stator 21 it is carried by a part 200, in the general shape of a plate, which is fixed to a sleeve 32; it is integral, both in rotation and in translation, of

the shaft 3 on which it is mounted.

  The starting of the electric motor 2 consequently results in the

  rotation of the sleeve 32 and, correspondingly, of the shaft 3 about its axis XX '.

  The flywheel 4 carries a damping system 5, working in

torsion, of known type.

  This damping system essentially comprises three parts, an annular part 40 rigidly fixed to the flywheel 4, for example by means of screws, a part (in the form of a sleeve) 50 centered on the shaft 3 and free to rotate relative to the latter. and an intermediate part 51, constituted by a device having a certain elasticity in torsion, which ensures the connection with a certain degree of freedom in

  rotation, between the flywheel 4 and the shaft 3 so as to avoid jolts.

  The mounting of the part 50 on the shaft 3 is ensured by means

  known type, for example a needle bearing.

  According to an essential characteristic of the invention, this part 50 is provided with clutching elements 52, materialized in the figure by bowls

  conical, the opening of which is directed to the left.

  Opposite these elements 52 are arranged clutching elements, in this case conical studs 60 directed to the right, which are carried by an annular part 6, guided in translation on a

  grooved sleeve 31 carried by the shaft 3.

  This representation is symbolic. The dog clutch could be obtained by axial fitting of a pinion in a complementary annular ring gear. The part 6 is therefore driven in rotation with the shaft 3, but can slide axially along XX ', in one direction or the other. To each element of

  male clutch 60 is associated with a female complementary element 52.

  The support 210 of the stator 21 of the electric motor 2 has a cylindrical annular opening of axis XX ', inside which is mounted and

  fixed a tubular part 7 which has the general shape of a sleeve.

  This sleeve constitutes the jacket of a hydraulic cylinder inside which is mounted a piston 8, also annular, capable of

slide axially along XX '.

  As seen in Figure 1, the piston 8 and the cylinder 7 are shaped so as to constitute a single-acting hydraulic cylinder, the pressure chamber, referenced 700, is located on the right side of the figure, towards

  the free end of the shaft 3 (on the side opposite the gearbox).

  Appropriate channels 72 formed in part 7 make it possible to supply this chamber from a source of hydraulic pressure equipping the

  vehicle, via an ad hoc control valve, not shown.

  Of course, the piston and the cylinder are provided with seals

  sealing, not shown.

  An elastic means, such as a helical spring 9, of axis XX ', acts

  on the piston 8, so as to move it normally to the right of the figure.

  Its force is determined to forcefully push the piston 8 in this direction in the event of depression or atmospheric pressure of the chamber 700. On the other hand, it is insufficient to oppose the displacement of the piston in the opposite direction (to the left) when the chamber 700 is under hydraulic pressure. In the example illustrated, this spring 9 is interposed between a base

  annular 70 of the part 7 and a recess 81 formed in the wall of the piston.

  The base 70 is advantageously an insert, screwed to

the end of part 7.

  The annular piston 8 carries the outer part 80 of a ball bearing cage, the balls of which are referenced 800 in the figure, and the cage of which

interior is referenced 62.

  The latter is integral with a cup 61 fixed to the sleeve 6

  above, which constitutes the walkman of the dog clutch system.

  Thanks to the ball bearing cage, the sleeve 6 is integral in axial translation with the piston 8, while being able to rotate relative to the latter at the same time as the rotary shaft 3, owing to the presence of the grooves on the

sleeve 31.

  The piston 8 is immobilized in rotation in the fixed cylinder 7.

  In the position illustrated in Figure 1, the system is declutched, the

  male elements 60 being separated from female elements 52.

  This state results from the pressurization of the chamber 700 of the jack

hydraulic 7, 8.

  If the heat engine 1 is stopped, and the electric motor 2 running, the input shaft 3 of the gearbox is driven directly and

  only by the rotating rotor 20.

  If we want to start the engine 1, we put the chamber 700 at atmospheric pressure, and the spring 9 pushes the assembly 8, 61, 6 to the right of the figure, in the direction of the part 50, as symbolized by the arrow F. The male parts 60 then snap into the bowls 52,

  ensuring the interconnection of parts 6 and 50.

  The shaft 10 is thus driven in rotation by the electric motor, via the damping system 5, which to a certain extent absorbs the shock due to the

dog clutch.

  This starts the engine 1.

  If the chamber 700 is kept under vacuum (or at atmospheric pressure), the thermal engine in operation then ensures the drive

  of shaft 3, via the dog clutch system.

  This training is carried out, even if the supply of the

electric motor 2.

  To uncouple the shaft 3 from the heat engine 1, it suffices to supply hydraulic pressure to the chamber 700, which causes the piston 8 to move to the left of the figure, against the force of

  compression of the spring 9, and realizes the declutching.

  The control of the system can be done automatically if necessary, thanks to speed sensors of the heat engine and the electric motor. Thus, it is possible for example to use the electric motor to start the heat engine or, when in electric mode, to switch to thermal mode by accelerating the heat engine and causing the dog clutch, as soon as the engine has started , when its speed of rotation becomes equal

to that of the electric motor.

  Because the actuation means of the dog clutch system are housed inside the electric motor, this hybrid powertrain is very

compact in axial direction.

Claims (8)

  1. Drive system for the primary shaft (3) of a gearbox for a hybrid propulsion vehicle, produced from a heat engine (1) and / or an electric motor (2), in which the 'primary shaft (3) is integral with the rotor (20) of the electric motor (2), characterized in that this primary shaft (3) is mounted coaxially at one end of the crankshaft (10) of the heat engine ( 1), and that a dog clutch system (6, 7) allows, selectively, either to make the crankshaft (10) rotate in rotation with said primary shaft (3), or,   on the contrary, to dissociate it.   2. System according to claim 1, characterized in that the   dog clutch system (6,7) is hydraulically operated.   3. System according to claim 2, characterized in that the control means of the dog clutch system (6, 7) comprise an annular hydraulic piston (8), which coaxially surrounds the primary shaft (3), and is   mounted fixed in rotation and movable in axial translation.   4. System according to claim 3, characterized in that said piston (8) acts via a rotary link (80, 800, 62) on a dog clutch (31) integral in rotation with the shaft primary (3), but mobile in axial translation thereon.   5. System according to claim 3 or 4, characterized in that said piston (8) is slidably mounted in a sleeve (7) integral with the stator (21) of said electric motor (2).   6. System according to one of claims 3 to 5, characterized by the   the fact that said piston (8) is permanently stressed by an elastic means such as a spring (9), which naturally tends to ensure the interconnection of the system (6, 7) in the absence of hydraulic pressure.   7. System according to one of the preceding claims, characterized   by the fact that the shaft end of the crankshaft (10) carries a flywheel (4), to which the dog clutch system (6, 7) is connected by means   shock absorber (5) working in torsion.   8. System according to the preceding claims, characterized by the   fact that the end portion (30) of the primary shaft (3) is centered and guided in rotation, by means of a rolling bearing (300), in a bore   at the end of the crankshaft (10).